The present invention relates to a housing for an electronic circuit and, more particularly, to such a housing designed to receive at least one electronic power component.
In current practice nowadays, use is made of electronic devices comprising a part referred to as the "power" part in which electric currents of substantial intensity give rise, in the components through which they flow, to a liberation of heat such that it is necessary to provide means for removal of this thermal energy. The active components comprising electrodes through which these currents flow, such as the collector of a power transistor for example, are particularly sensitive to a rise of temperature, and it is necessary to ensure their cooling in order that their operating characteristics should not be effected thereby.
In order to do this, in current practice there is welded onto the collector of a power transistor a metal plate of larger surface, constructed of copper for example, in order to increase the thermal radiation, it being possible for this plate itself to be electrically connected to an external connecting pin by a wire welded at its two ends, or by a conductive track engraved or deposited and welds at the ends of this track. The plate itself may be fixed on a substrate, constructed of ceramic for example, which is electrically insulating but nevertheless of low thermal resistance, this substrate being itself in thermal contact with a heat sink. A description is given of a housing comprising such an arrangement of plates and of welds or linkages in French Pat. No. 2,570,877. European Application No. 78,684 and U.S. Pat. No. 3,972,062 describe other housings or mountings of power components in which an electrode is arranged in such a manner as to fulfil both a thermal function and an electrical function.
These known housings comprise a large number of welds or other linkages which make more difficult the thermal transfers which are necessary for the cooling of the power component, while complicating the mounting and thus diminishing its reliability. Furthermore, they are not adapted for the reception of more than one power component, or for the simultaneous reception of other active or passive components, as is, in current practice, now found in numerous electronic circuits such as circuits for the command of actuators comprising a computation section and a power section. By way of non-limiting example of applications of circuits of this type, it is possible to mention the command of an internal combustion engine ignition coil.
The object of the present invention is therefore to provide a housing for an electronic circuit comprising at least one power component, this housing being equipped with means for thermal and electrical functions ensuring, with a minimum number of welds or other linkages, the cooling of the component by means of one of its electrodes and the electrical linkage of this electrode to an external connecting pin of the housing.
The object of the present invention is also to provide such a housing designed to receive, besides power components associated with these means having a thermal and electronic function, other components which can be mounted in the traditional manner and connected to other external connecting pins of the housing.
These objects of the invention are achieved with a housing for an electronic circuit comprising at least one electronic power component, equipped with at least one radiator exhibiting a surface arranged to be in thermal and electrical contact with an electrode of the component, wherein said surface of the radiator is flush on a face of an internal wall of the housing, while the other faces of the radiator are embedded in this wall, and wherein an electrical connecting pin is formed in one piece with the radiator, this pin extending in the thickness of at least said wall of the housing, to emerge from the latter in an external connecting position.
By virtue of the radiator having a connecting pin integrated with the housing according to the invention, this radiator has imparted thereto a two-fold thermal and electrical function at the cost of a minimum number of welds or other linkages, as will be explained hereinbelow in association with the examination of the accompanying drawing, in which: